The present invention relates to a bone anchoring device. In particular, it relates to a bone anchoring device which comprises a first section with elastically deformable barb elements for push and turn insertion and an additional second section with a bone thread for enhanced retention in the bone. The bone anchoring device can be used for example in the form of a pedicle screw for the application in spinal surgery or in any other type of bone anchor application.
A known form of a bone anchoring element is a conventional bone screw comprising a shaft with a bone thread for screwing the screw into a bone. The bone screw is manually inserted into the bone by means of a screw driver, which is a time-consuming and force-requiring process. Moreover, during the process in which the screw is inserted into the bone, high pressure forces may be acting on the bone structure itself, which is undesirable in certain clinical applications such as e.g., in neuro surgery, spinal surgery, pediatric surgery or trauma surgery.
U.S. Pat. No. 5,562,704 discloses a surgical implant having a body with a first end formed as a stem and a second end formed as a head. The implant comprises a plurality of cuts defining barbs which are intended to keep the implant installed in the position of use.
US 2005/0187555 A1 discloses a bone anchoring element comprising a shaft with a plurality of elastically deformable barb elements which are arranged in at least one helical line around the shaft. The design of the bone anchoring device allows a fast and easy insertion into the bone. Therefore, it is a so-called push and turn anchor. However, the pull-out force may be reduced depending on the bone quality compared to conventional bone screws. In one embodiment the bone anchoring device comprises a first section having the barb elements which is located near the tip, and adjacent to the first section, a second section having a metric thread onto which an outer nut can be screwed to fix a bone plate to the bone.
Based on the foregoing, there is a need to provide a bone anchoring device which can be inserted by pushing it into the bone and which at the same time offers increased resistance against pull-out and rotational forces.